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Hw chapter 3 erth 17
study flash cards
| Question | Answer |
|---|---|
| The idea that the continents are slowly moving about Earth's surface is called Blank______ drift. | continental drift |
| Select all the lines of evidence Wegener used to support his theory of continental drift. | The fossils of plants and animals, The geographic fit of the continents, Patterns of glaciation |
| The lack of a viable driving mechanism was the main objection to the theory of continental drift when it was first proposed. True false question. | true |
| A convection cell in the mantle is the Blank______. path mantle material takes to revolve around Earth's core pattern of movement mantle material takes as it heats and cools path tectonic plates take once they subduct into Earth | pattern of movement mantle material takes as it heats and cools |
| Whole-mantle convection differs from the other model of mantle convection in that the other model suggests convection is Multiple choice question split between the upper and lower mantle | split between the upper and lower mantle |
| A major line of evidence for continental drift is that unusual sequences of rocks, unique fossils, and glacial deposits lined up with magnetic field lines across ocean basins across major faults | across ocean basins |
| The main reason continental drift was not widely accepted at the time of its proposal was Blank______. Multiple choice question. | there was not an acceptable mechanism identified for causing the drift |
| A Blank______ cell is the pattern mantle material takes as it rises when heated, then moves laterally as it cools, and sinks once its density is great enough. | convection |
| Seafloor spreading is Blank______. the lateral movement of the oceanic lithosphere near spreading centers where oceanic crust subducts beneath another tectonic section or plate the thermal expansion of basalt heated near hotspot volcanoes | the lateral movement of the oceanic lithosphere near spreading centers |
| The difference between an earthquake's epicenter and hypocenter (focus) is an epicenter is the point Blank______. | on Earth's surface directly above an earthquake, and the hypocenter is the point within Earth where the earthquake occurs |
| The lateral movement of the oceanic lithosphere near ocean ridges is called seafloor | spreading |
| The areas in which new sea floor and oceanic lithosphere are formed are called ____ enters, and the areas where older oceanic lithosphere is recycled as it descends and melts are called ____ | spreading centers and subduction zones |
| Heat flow on Earth's surface is greatest at Blank______. Multiple choice question. mid-ocean ridges all plate boundaries subduction zones continental rifts | mid-ocean ridges |
| The oldest rocks in the ocean (about 200 million years) are much_____ | younger |
| The vertical, cylindric rock sections that are obtained by drilling into the sea floor are called Blank______. poles logs cores slides | cores |
| the average age of the rocks that comprise the oceanic and continental crust. The oceanic crust is generally older than the continental crust The oceanic crust is generally younger than the continental crust. | The oceanic crust is generally younger than the continental crust. |
| Earth's magnetic field consists of Blank______ opposing pole(s). This is called a Blank______. = | two, dipole |
| Select all the evidence the Glomar Challenger provided to support the theory of seafloor spreading. | No oceanic crust older than 180 million years was found. Sediment age and thickness increases outward from the ocean ridge system. |
| The magnetic field of Earth not constant. The locations of the north and south magnetic poles change over time, as does their strength stable in that the locations of the poles are fixed, but the strength of the field changes with time | not constant. The locations of the north and south magnetic poles change over time, as does their strength |
| Earth's magnetic field is similar to what would be expected if a giant bar magnet was located within Earth. about 45.5ο off Earth's axis of rotation with the geographic North and South Poles about 11.5ο off Earth's axis of rotation | about 11.5ο off Earth's axis of rotation |
| Basalt, the most common rock of the oceanic crust, can record the orientation of the magnetic field at the time of its formation because Blank______. | the magnetic mineral magnetite aligns itself with Earth's magnetic field before the molten rock fully cools |
| If a freely suspended magnet is pointing vertically downward with its north-seeking end, the magnet is likely at Blank______. the north magnetic pole the south magnetic pole | the north magnetic pole |
| The Curie temperature is the temperature below which Blank______. | the magnetic orientation of a rock's magnetic grains are locked in place |
| Paleomagnetism is the investigation of the fossil magnetism in rocks effects magnetism can have on the brains of animals effects felt by ecosystems during and after magnetic reversals magnetic systems used by past peoples and cultures | fossil magnetism in rocks |
| A polar ______occurs when the north magnetic field and the south magnetic field switch orientations. | reversal |
| Changes in the liquid outer____ are likely the cause of the magnetic reversals of the poles. | core |
| Magnetic maps of the sea floor were made during the 1950s towing marine magnetometers behind ships using satellites to detect the magnetic signatures of the sea floor | towing marine magnetometers behind ships |
| Since the magnetic anomalies on either side of a spreading center can be matched up and the age can be determined by using known magnetic reversals, the magnetic anomalies can be used to indicate the Blank______ | rate of seafloor spreading |
| If you were to study ___you would study the magnetism of ancient rocks. | paleomagnetism |
| Magnetic reversal are most likely associated with Blank______. large solar flares that disrupt the magnetic shield around the Earth changes in the motion of material in Earth's liquid outer core | changes in the motion of material in Earth's liquid outer core |
| Oceanographers used magnetometers in the 1950s to create magnetic maps of the | ocean floor |
| The age of the sea floor Blank______ away from the ocean spreading centers. Multiple choice question. decreases is random increases is unknown | increases |
| The theory of ocean___________incorporates the ideas of both seafloor spreading and continental drift into a unified | plate tectonics |
| The theory that describes the movement and fragmentation of the lithosphere into seven major plates along with a number of minor ones is called Blank______. Multiple choice question. plate tectonics continental drift | plate tectonics |
| The youngest sea floor can be found Blank______. in the middle of oceanic plates at subduction zones near the continental end of passive margins at spreading centers | at spreading centers |
| Marine convergent boundaries are associated with: Multiple choice question. opening of ocean basins. deep-ocean trenches. creation of massive mountain ranges. the creation of sea floor. | deep ocean trenches |
| A sunken rift zone can be described as______a down-dropped elongate block of earth. | graben |
| Pillow lavas are created from____ lava that is extruded slowly onto the ocean floor. | basalt |
| A continental____zone is associated with mantle upwelling, weakening crust, and extensional forces. | rift |
| Escarpments on the sea floor mark a difference in the____ on either side of a transform boundary caused by age and temperature of the crustal segments. | elevation |
| Basaltic magma that is extruded slowly onto the sea floor tends to cool quickly into rounded flows called Blank______ basalts. Multiple choice question. stromboli incorrect pillow bean bag cushion | pillow |
| The ocean ridge system is divided into segments that are separated by transform faults | basalt |
| A fracture zone is a continuous linear feature of segments of active transform faults and subduction zones between them island-arc volcanoes a line of pillow basalts between them "fossil" or inactive transform faults | fossil |
| Transform faults within a ridge system form because of changes in the speed and direction of moving plates on a ____ surface, i.e, Earth. | spherical |
| ectonic plates move toward each other at transform____ boundaries. | convergent |
| Which of the following is a type of volcano that may erupt explosively and eject rock, ash, and gas that rises high into the atmosphere? Multiple choice question. Aridontic Andesitic Metallic Pedesitic | Andesitic |
| The characteristics listed below apply either to active or passive margins. select all Ocean trenches possible Represents a plate boundary Broad and shallow with thick sedimentary deposits Modified by tectonic movement and volcanoes | oceans trenches possible, modified by tectonic movement, represent plate boundary |
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